fixed focus lens

Abstract

The application discloses a fixed-focus lens, which comprises, in sequence from the object side to the image side along the optical axis, a first lens with positive refractive power, the object side of which is a convex surface; a second lens with refractive power; a third lens with refractive power; a fourth lens, the object side of which is a convex surface; a fifth lens with refractive power; and a sixth lens with negative refractive power, the object side and the image side of which are both concave surfaces, wherein the second lens and the third lens have opposite positive and negative refractive power; the image side of the first lens and the image side of the fifth lens are both convex or both concave; the effective focal length F6 of the sixth lens, the radius of curvature R61 of the object side of the sixth lens, and the radius of curvature R62 of the image side of the sixth lens satisfy: 1.6 mm <= |(R61+R62)*F6 / (R61-R62)| <= 3.49 mm.

Description

Technical Field

[0001] This application relates to the field of optical components, and more specifically, to a fixed-focus lens. Background Technology

[0002] With the continuous upgrading and development of Internet technology, video cameras are widely used in video conferencing, online teaching, and online video shooting, and have received increasing attention from the public. As a result, the requirements for their image quality are also getting higher and higher.

[0003] However, currently used video conferencing cameras generally have the following shortcomings:

[0004] 1. The image size of the video conferencing camera is too small;

[0005] 2. Current video conferencing lenses often suffer from poor distortion control when achieving a wide field of view and large image size, resulting in significant distortion of the captured images and affecting post-processing.

[0006] 3. Current video conferencing lens configurations make it difficult to effectively correct system aberrations, resulting in poor image quality.

[0007] 4. To improve the optical imaging quality of current video conferencing lenses, it is necessary to increase the number of lenses. This results in an excessively long overall lens and a large size, leading to excessively high overall cost and weight.

[0008] Therefore, in summary, designing a fixed-focus lens with low distortion, small size, large image sensor size, high resolution, and low cost has become a market trend. Summary of the Invention

[0009] According to an embodiment of this application, a fixed-focus lens is provided, comprising, sequentially from the object side to the image side along the optical axis: a first lens having positive optical power, the object side of which is convex; a second lens having optical power, the object side of which is concave and the image side of which is convex when the optical power of the second lens is positive; the object side of which is convex and the image side of which is concave when the optical power of the second lens is negative; a third lens having optical power, the image side of which is convex when the optical power of the third lens is positive; the image side of which is concave when the optical power of the third lens is negative; a fourth lens having a convex object side; and a fifth lens having optical power, the object side of which is convex when the optical power of the fifth lens is negative; a fourth lens having a convex object side; and a fifth lens having optical power, the object side of which is convex when the optical power of the fifth lens is positive. When the optical power of the lens is positive, its object-side surface is convex; when the optical power of the fifth lens is negative, its object-side surface is concave; and the sixth lens with negative optical power has both its object-side and image-side surfaces concave. The optical power of the second and third lenses has opposite positive and negative attributes; the image-side surfaces of the first and fifth lenses are either both convex or both concave; the effective focal length F6 of the sixth lens, the radius of curvature R61 of the object-side surface of the sixth lens, and the radius of curvature R62 of the image-side surface of the sixth lens satisfy: 1.6mm≤|(R61+R62)*F6 / (R61-R62)|≤3.49mm.

[0010] In one or more embodiments, the Abbe number Vd1 of the first lens and the effective focal length F1 of the first lens satisfy: 3.48≤Vd1 / F1≤7.73.

[0011] In one or more embodiments, the effective focal length F1 of the first lens and the radius of curvature R11 of the object side surface of the first lens satisfy: 1.80≤F1 / R11≤2.16.

[0012] In one or more embodiments, the combined effective focal length F23 of the second lens and the third lens satisfies the following condition with respect to the total effective focal length F of the fixed-focus lens: 1.5 ≤ |F23 / F| ≤ 7.5.

[0013] In one or more embodiments, the combined effective focal length of the second lens and the third lens, the center thickness value d2 of the second lens, and the center thickness value d3 of the third lens satisfy: 12≤|F23 / (d2+d3)|≤32.

[0014] In one or more embodiments, the effective focal length F4 of the fourth lens, the radius of curvature R41 of the object side of the fourth lens, and the radius of curvature R42 of the image side of the fourth lens satisfy: 0.2≤|F4 / (R41+R42)|≤4.3.

[0015] In one or more embodiments, the combined effective focal length F56 of the fifth and sixth lenses satisfies the condition that -1.5 ≤ F56 / F ≤ -0.23 with respect to the total effective focal length F of the fixed-focus lens.

[0016] In one or more embodiments, the radius of curvature R12 of the image-side surface of the first lens and the radius of curvature R52 of the image-side surface of the fifth lens satisfy: 1≤|(R12+R52) / (R12-R52)|≤7.5.

[0017] In one or more embodiments, the total optical system length TTL of the fixed-focus lens and half the diagonal length H of the effective pixel area on the imaging plane of the fixed-focus lens satisfy: 1.98≤TTL / H≤2.4.

[0018] In one or more embodiments, the total optical system length TTL of the fixed-focus lens and the total effective focal length F of the fixed-focus lens satisfy: 1.21≤TTL / F≤1.47.

[0019] In one or more embodiments, the maximum value CTmax of the center thickness of each lens on the optical axis and the minimum value CTmin of the center thickness of each lens on the optical axis in the fixed-focus lens satisfy: 3.62≤CTmax / CTmin≤5.2.

[0020] In one or more embodiments, the center thickness value d4 of the fourth lens and the refractive index Nd4 of the fourth lens satisfy the following condition: 0.7≤d4 / Nd4≤2.1.

[0021] In one or more embodiments, the radius of curvature R51 of the object side of the fifth lens and the radius of curvature R52 of the image side of the fifth lens satisfy: -3.2≤(R51+R52) / (R51-R52)≤-0.75.

[0022] In one or more embodiments, the radius of curvature R21 of the object-side surface of the second lens, the radius of curvature R22 of the image-side surface of the second lens, the radius of curvature R31 of the object-side surface of the third lens, and the radius of curvature R32 of the image-side surface of the third lens satisfy: 0.22 ≤ |(R21+R22) / (R31+R32)| ≤ 2.9. In one or more embodiments, the total effective focal length of the fixed-focus lens and half the diagonal length H of the effective pixel area on the imaging plane of the fixed-focus lens satisfy: 1.58 ≤ F / H ≤ 1.66.

[0023] In one or more embodiments, the fixed-focus lens satisfies at least one of the following conditions: 0.24≤|(R21+R22) / (R31+R32)|≤2.9; |(R21+R22) / (R31+R32)|=97.01; 4.09≤Vd1 / F1≤7.12; 1.89≤F1 / R11≤2.01; 1.57≤|F23 / F|≤7.16; 12.33≤|F23 / (d2+d3)|≤30.75; 0.2≤|F4 / (R41+R42)|≤4.3; -1.32≤F56 / F≤-0.42; 1.02≤| (R12+R52) / (R12-R52)|≤7.5; |(R12+R52) / (R12-R52)|=18.08; 2.02≤TTL / H≤2.24; 1.24≤TTL / F≤1.35; 3.64≤CTmax / CTmin≤4.95; 0.71≤d4 / Nd4≤1.95; -3.08≤(R51+R52) / (R51-R52)≤-0.89; 1.63mm≤|(R61+R62)*F6 / (R61-R62)|≤2.98mm; 1.64≤F / H≤1.66; where, R R21 is the radius of curvature of the object-side surface of the second lens, R22 is the radius of curvature of the image-side surface of the second lens, Vd1 is the Abbe number of the first lens, F1 is the effective focal length of the first lens, R11 is the radius of curvature of the object-side surface of the first lens, F23 is the combined effective focal length of the second and third lenses, F is the total effective focal length of the fixed-focus lens, d2 is the center thickness value of the second lens, d3 is the center thickness value of the third lens, F4 is the effective focal length of the fourth lens, R41 is the radius of curvature of the object-side surface of the fourth lens, R42 is the radius of curvature of the image-side surface of the fourth lens, F56 is the combined effective focal length of the fifth and sixth lenses, R1 R2 is the radius of curvature of the image-side surface of the first lens, R52 is the radius of curvature of the image-side surface of the fifth lens, TTL is the total length of the optical system of the fixed-focus lens, H is half the diagonal length of the effective pixel area on the imaging plane of the fixed-focus lens, CTmax is the maximum value of the center thickness of each lens in the fixed-focus lens on the optical axis, CTmin is the minimum value of the center thickness of each lens in the fixed-focus lens on the optical axis, d4 is the center thickness value of the fourth lens, Nd4 is the refractive index of the fourth lens, R51 is the radius of curvature of the object-side surface of the fifth lens, R61 is the radius of curvature of the object-side surface of the sixth lens, and R62 is the radius of curvature of the image-side surface of the sixth lens.

[0024] In one or more embodiments, the first lens is a glass lens, and the second to sixth lenses are plastic lenses.

[0025] According to the embodiments of this application, a fixed-focus lens with a large target surface, low distortion, large field of view, and miniaturization is provided. While satisfying the requirements of low distortion with an absolute value of less than 1.85% and a total optical system length (TTL) of less than 21mm, it can achieve a field of view (FOV) of ≥63° and a large target surface with a matching target surface of up to 17mm. Attached Figure Description

[0026] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0027] Figure 1 A schematic diagram of the structure of a fixed-focus lens according to Embodiment 1 of this application is shown;

[0028] Figure 2 The optical distortion curve of the fixed-focus lens in Embodiment 1 of this application is shown;

[0029] Figure 3 A schematic diagram of the structure of a fixed-focus lens according to Embodiment 2 of this application is shown;

[0030] Figure 4 The optical distortion curve of the fixed-focus lens in Embodiment 2 of this application is shown;

[0031] Figure 5 A schematic diagram of the structure of a fixed-focus lens according to Embodiment 3 of this application is shown;

[0032] Figure 6 The optical distortion curve of the fixed-focus lens in Embodiment 3 of this application is shown;

[0033] Figure 7 A schematic diagram of the structure of a fixed-focus lens according to Embodiment 4 of this application is shown; and

[0034] Figure 8 An optical distortion curve of the fixed-focus lens in Embodiment 4 of this application is shown. Detailed Implementation

[0035] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0036] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of this application, the first lens discussed below may also be referred to as the second lens or the first lens.

[0037] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0038] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0039] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0040] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formalized sense, unless expressly so specified herein.

[0041] It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other. The following embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be pointed out that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application.

[0042] The features, principles and other aspects of this application are described in detail below.

[0043] refer to Figure 1 As shown, a fixed-focus lens according to an exemplary embodiment of this application may include a first lens L1 with positive optical power arranged sequentially along the optical axis from the object side (the side where light is incident) to the image side (the side where light is emitted), the object side of which is convex; a second lens L2 with optical power, wherein when the optical power of the second lens L2 is positive, its object side is concave and its image side is convex, and when the optical power of the second lens L2 is negative, its object side is convex and its image side is concave; and a second lens L2 with optical power of [missing information]. The third lens L3 has a positive optical power, and its image-side surface is convex when the optical power of the third lens L3 is positive, and its image-side surface is concave when the optical power of the third lens L3 is negative; the fourth lens L4 has a convex object-side surface; the fifth lens L5 has a positive optical power, and its object-side surface is convex when the optical power of the fifth lens L5 is positive, and its object-side surface is concave when the optical power of the fifth lens L5 is negative; and the sixth lens L6 has a negative optical power, and both its object-side surface and image-side surface are concave.

[0044] In an exemplary embodiment, the second lens L2 and the third lens L3 of the fixed-focus lens have opposite positive and negative optical power properties.

[0045] According to the fixed-focus lens of the present application, the first lens L1 has positive optical power and the lens shape is convex with the object side facing, which can converge incident light rays with a large field of view into the optical system as much as possible, expand the field of view of the optical system, and make the field of view FOV ≥ 63°; at the same time, it can introduce negative distortion, effectively balance and correct the distortion generated by the system behind the lens, and achieve an absolute value of optical distortion of less than or equal to 1.85%.

[0046] According to the fixed-focus lens of this application, the second lens L2 can have positive optical power and a meniscus shape with the convex side facing the image side. When properly matched with the third lens L3, which has negative optical power and a concave shape on the image side, it can effectively control the trajectory of the incident light in the optical system, raise the light beam to meet the requirements of a large target size, allow more light to enter the optical system, improve the relative illumination of the lens, better balance various aberrations of the optical system, and effectively correct the optical distortion of the optical system, making the absolute value of optical distortion less than or equal to 1.85%, reducing the degree of image distortion, and improving the imaging quality of the optical system.

[0047] According to the fixed-focus lens of this application, the second lens L2 may have negative optical power and a meniscus shape with the concave side facing the image side. When properly matched with the third lens L3, which has positive optical power and a convex shape on the image side, it can effectively control the trajectory of incident light in the optical system, raise the light beam to meet the requirements of a large target size, allow more light to enter the optical system, improve the relative illumination of the lens, better balance various aberrations of the optical system, and effectively correct the optical distortion of the optical system, making the absolute value of optical distortion less than or equal to 1.85%, reducing the degree of image distortion, and improving the imaging quality of the optical system.

[0048] In an exemplary embodiment, the object-side surface of the fourth lens L4 of the fixed-focus lens is convex, which can effectively control the direction of light, enable the light to be transmitted smoothly, suppress the generation of astigmatism, and effectively correct field curvature, thereby greatly improving the imaging performance of the optical system.

[0049] In an exemplary embodiment, the fifth lens L5 may have positive optical power and the object side of the lens may be convex, which is beneficial for suppressing astigmatism and effectively correcting field curvature, thereby improving the imaging quality of the optical system. Furthermore, the image side of the fifth lens L5 may have the same shape as the image side of the first lens L1, such as both being convex or both being concave. Through reasonable matching, the optical distortion of the optical system can be effectively corrected, the degree of image distortion can be reduced, and the imaging quality can be improved.

[0050] In an exemplary embodiment, the fifth lens L5 may have negative optical power and the object side of the lens may be concave, which is beneficial for suppressing astigmatism and effectively correcting field curvature, thereby improving the imaging quality of the optical system. Furthermore, the shape of the image side of the fifth lens L5 may be the same as that of the image side of the first lens L1, such as both being convex or both being concave. Through reasonable matching, the optical distortion of the optical system can be effectively corrected, the degree of image distortion can be reduced, and the imaging quality can be improved.

[0051] In an exemplary embodiment, the sixth lens L6 has negative optical power, and both the object side and the image side of the lens are concave, which is beneficial for controlling the light path and raising the light, so that the matching target surface of the optical lens can reach 17mm; at the same time, it can effectively correct the optical distortion of the off-axis field of view, so that the absolute value of the optical distortion is less than or equal to 1.85%, which is beneficial for reducing the degree of image distortion and greatly improving the imaging performance of the optical system.

[0052] In an exemplary embodiment, the fixed-focus lens may include an aperture stop STO, which can effectively gather the light entering the optical system, reduce the maximum aperture of the optical system, and facilitate miniaturization. The aperture stop STO may be disposed, for example, on the object side of the first lens L1, between the first lens L1 and the second lens L2, or between the second lens L2 and the third lens L3. This application does not specifically limit its position.

[0053] In an exemplary embodiment, the fixed-focus lens may include a protective glass for protecting the image sensor, which may be located, for example, between the sixth lens L6 and the imaging surface of the optical system.

[0054] According to the exemplary embodiments of this application, the fixed-focus lens can satisfy the following condition: 0.22≤|(R21+R22) / (R31+R32)|≤2.9, where R21 is the radius of curvature of the object-side surface of the second lens, R22 is the radius of curvature of the image-side surface of the second lens, R31 is the radius of curvature of the object-side surface of the third lens, and R32 is the radius of curvature of the image-side surface of the third lens. By reasonably configuring the radii of curvature of the object-side and image-side surfaces of the second and third lenses, the light path can be effectively controlled, the light beam can be raised to meet the requirements of a large target surface size, and the matching target surface can reach 17mm; at the same time, more light can enter the optical system, improving the relative illumination of the lens, and making the edge relative illumination ≥50%.

[0055] In an exemplary embodiment, the first lens L1 may be made of glass, while the other lenses may be made of plastic. Using a hybrid glass-plastic lens helps reduce the cost of the optical system and also helps balance the high and low temperature performance of the fixed-focus lens, achieving high image quality within the range of -20℃ to 60℃. Furthermore, using glass for the first lens L1 helps correct chromatic aberration in the optical system and improves the saturation of the lens colors.

[0056] In an exemplary embodiment, the fixed-focus lens satisfies the following condition: 3.48 ≤ Vd1 / F1 ≤ 7.73, where Vd1 is the Abbe number of the first lens L1 and F1 is the effective focal length of the first lens L1. The first lens is made of glass, and by reasonably configuring the ratio of the Abbe number of the first lens to the effective focal length of the first lens, the system chromatic aberration can be effectively corrected, which is beneficial to improving the color saturation of the lens.

[0057] In an exemplary embodiment, the fixed-focus lens satisfies the following condition: 1.80 ≤ F1 / R11 ≤ 2.16, where F1 is the effective focal length of the first lens and R11 is the radius of curvature of the object-side surface of the first lens. By rationally configuring the ratio of the radius of curvature of the object-side surface of the first lens to the effective focal length, it is beneficial to converge large-angle light rays into the optical system, effectively expanding the field of view of the optical system to FOV ≥ 63°; at the same time, negative distortion can be introduced to effectively balance and correct the distortion generated by the system behind the lens, achieving an absolute value of optical distortion of less than or equal to 1.85%.

[0058] In an exemplary embodiment, the fixed-focus lens satisfies the following condition: 1.5 ≤ |F23 / F| ≤ 7.5, where F23 is the combined effective focal length of the second and third lenses, and F is the total effective focal length of the fixed-focus lens. By rationally configuring the ratio between the combined effective focal length of the second and third lenses and the total effective focal length of the fixed-focus lens, optical distortion of the optical system can be effectively corrected, which helps to reduce the degree of image distortion and greatly improves the imaging performance of the optical system.

[0059] In an exemplary embodiment, the fixed-focus lens satisfies the following condition: 12 ≤ |F23 / (d2+d3)| ≤ 32, where F23 is the combined effective focal length of the second and third lenses, d2 is the center thickness value of the second lens, and d3 is the center thickness value of the third lens. By rationally configuring the ratio between the combined effective focal length of the second and third lenses and their center thickness values, light can be transmitted smoothly, effectively correcting spherical aberration and astigmatism of the optical system, greatly improving the imaging performance of the optical system; at the same time, it can effectively correct the optical distortion of the optical system, making the absolute value of optical distortion less than or equal to 1.85%, which helps to reduce the degree of image distortion and greatly improves the imaging performance of the optical system.

[0060] In an exemplary embodiment, the fixed-focus lens satisfies the following condition: 0.2 ≤ |F4 / (R41+R42)| ≤ 4.3, where F4 is the effective focal length of the fourth lens, R41 is the radius of curvature of the object-side surface of the fourth lens, and R42 is the radius of curvature of the image-side surface of the fourth lens. By rationally configuring the effective focal length of the fourth lens and the radii of curvature of its object-side and image-side surfaces, the trajectory of light can be effectively controlled, allowing light to be transmitted smoothly, suppressing astigmatism, and effectively correcting field curvature, thus greatly improving the imaging performance of the optical system.

[0061] In an exemplary embodiment, the fixed-focus lens satisfies the following condition: -1.5 ≤ F56 / F ≤ -0.23, where F56 is the combined effective focal length of the fifth and sixth lenses, and F is the total effective focal length of the fixed-focus lens. By reasonably configuring the ratio of the combined effective focal length of the fifth and sixth lenses to the total effective focal length of the optical lens, optical distortion in the off-axis field of view can be effectively corrected, making the absolute value of optical distortion less than or equal to 1.85%, thus greatly reducing the degree of image distortion.

[0062] In an exemplary embodiment, the fixed-focus lens satisfies the following condition: 1 ≤ |(R12+R52) / (R12-R52)| ≤ 7.5, where R12 is the radius of curvature of the image-side surface of the first lens, and R52 is the radius of curvature of the image-side surface of the fifth lens. By reasonably controlling the radius of curvature of the image-side surfaces of the fifth lens and the first lens, and making the shape of the image-side surface of the fifth lens the same as that of the first lens, the direction of light can be effectively controlled, allowing for a smooth transition of light, thereby effectively suppressing astigmatism; at the same time, negative distortion is introduced to effectively correct the optical distortion of the optical system, reduce the degree of image distortion, and improve image quality.

[0063] In an exemplary embodiment, the fixed-focus lens satisfies the following condition: 1.98 ≤ TTL / H ≤ 2.4, where TTL is the total length of the optical system of the fixed-focus lens, and H is half the diagonal length of the effective pixel area on the imaging plane of the fixed-focus lens. With a fixed system image height, controlling the total length of the optical system of the fixed-focus lens to make it smaller (TTL < 21mm) is beneficial for miniaturization.

[0064] In an exemplary embodiment, the fixed-focus lens satisfies the following condition: 1.21 ≤ TTL / F ≤ 1.47, where TTL is the total length of the optical system of the fixed-focus lens, and F is the total effective focal length of the fixed-focus lens. With a fixed total effective focal length of the optical system, by controlling the ratio of the total optical system length to the total effective focal length, the total optical length of the system can be made smaller, which is beneficial for lens miniaturization, ensuring that the total optical system length TTL < 21mm.

[0065] In an exemplary embodiment, the fixed-focus lens satisfies the following condition: 3.62 ≤ CTmax / CTmin ≤ 5.2, where CTmax is the maximum value of the center thickness of each lens in the fixed-focus lens along the optical axis, and CTmin is the minimum value of the center thickness of each lens in the fixed-focus lens along the optical axis. By reasonably controlling the thickness of each lens in the fixed-focus lens, it is beneficial to ensure the stable function of each lens, to minimize changes in light trajectory under high and low temperatures, and to achieve heat-free lens operation.

[0066] In an exemplary embodiment, the fixed-focus lens satisfies the following condition: 0.7 ≤ d4 / Nd4 ≤ 2.1, where d4 is the center thickness of the fourth lens and Nd4 is the refractive index of the fourth lens. By reasonably controlling the center thickness and refractive index of the fourth lens, it is beneficial to reduce the tolerance sensitivity of the fourth lens and improve the lens production yield.

[0067] In an exemplary embodiment, the fixed-focus lens satisfies the following condition: -3.2 ≤ (R51 + R52) / (R51 - R52) ≤ -0.75, where R51 is the radius of curvature of the object-side surface of the fifth lens, and R52 is the radius of curvature of the image-side surface of the fifth lens. By rationally configuring the radii of curvature of the object-side and image-side surfaces of the fifth lens, the direction of light can be effectively controlled, the deflection angle of the incident and outgoing light rays of the fifth lens can be reduced, and the light can enter the rear of the optical system smoothly, reducing tolerance sensitivity and improving lens yield.

[0068] In an exemplary embodiment, the fixed-focus lens satisfies the following condition: 1.6 ≤ |(R61+R62)*F6 / (R61-R62)| ≤ 3.49, where F6 is the effective focal length of the sixth lens, R61 is the radius of curvature of the object-side surface of the sixth lens, and R62 is the radius of curvature of the image-side surface of the sixth lens. By rationally configuring the radii of curvature of the object-side and image-side surfaces of the sixth lens with the effective focal length, the light path can be effectively controlled, the deflection angle of the incident and outgoing rays of the sixth lens can be reduced, and the light can smoothly transition from the sixth lens to the imaging plane, reducing the tolerance sensitivity of the sixth lens and improving the lens assembly yield.

[0069] In an exemplary embodiment, the fixed-focus lens satisfies the following condition: 1.58 ≤ F / H ≤ 1.66, where F is the total effective focal length of the fixed-focus lens, and H is half the diagonal length of the effective pixel area on the imaging plane of the fixed-focus lens. With a fixed total effective focal length of the optical system of the fixed-focus lens, by optimizing the system image height, a larger image height value is achieved, which is beneficial for realizing a large target surface, allowing half the diagonal length H of the imaging chip of the fixed-focus lens to reach 8.5mm.

[0070] In an exemplary embodiment, the object-side or image-side surface of at least one lens in a fixed-focus lens can be aspherical. Aspherical lenses have better radius of curvature characteristics, which has the advantage of improving distortion aberrations and astigmatism aberrations. By using aspherical lenses, aberrations that occur during imaging can be eliminated as much as possible, thereby improving image quality.

[0071] The fixed-focus lens according to the embodiments of this application can achieve low distortion, with an absolute optical distortion value of ≤1.85%.

[0072] The fixed-focus lens according to the embodiments of this application can be miniaturized, with a total optical system length TTL < 21 mm.

[0073] The fixed-focus lens according to the embodiments of this application can achieve a large target surface, with a target surface of up to 17mm.

[0074] The fixed-focus lens according to the embodiments of this application can achieve a large field of view, with a field of view FOV ≥ 63°.

[0075] The fixed-focus lens according to the embodiments of this application can achieve an edge relative illumination of ≥50%.

[0076] The following describes in further detail, with reference to the accompanying drawings, specific embodiments of a fixed-focus lens applicable to the above-described embodiments.

[0077] Example 1

[0078] The following is for reference Figure 1 and Figure 2 Describes a fixed-focus lens according to Embodiment 1 of this application.

[0079] like Figure 1 As shown, in this embodiment, the fixed-focus lens includes, in sequence along the optical axis from the object side to the image side: a first lens L1, an aperture stop STO, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6.

[0080] In this embodiment, the first lens L1 has positive optical power, with its object-side surface surf1 being convex and its image-side surface surf2 being convex; the second lens L2 has negative optical power, with its object-side surface surf4 being convex and its image-side surface surf5 being concave; the third lens L3 has positive optical power, with its object-side surface surf6 being concave and its image-side surface surf7 being convex; the fourth lens L4 has positive optical power, with its object-side surface surf8 being convex and its image-side surface surf9 being convex; the fifth lens L5 has negative optical power, with its object-side surface surf10 being concave and its image-side surface surf11 being convex; and the sixth lens L6 has negative optical power, with its object-side surface surf12 being concave and its image-side surface surf13 being concave. The protective glass CG has an object-side surface surf14 and an image-side surface surf15. Light incident from the object side passes sequentially through the surfaces of each optical element and is finally imaged onto the imaging surface (IMA) surf16.

[0081] In this embodiment, the first lens L1 is made of glass, while the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are all made of plastic.

[0082] Table 1 shows some basic parameters of each lens in the fixed-focus lens of this embodiment, including surface type, radius of curvature, thickness, refractive index of the material, and Abbe number. The units for radius of curvature and thickness / distance are millimeters (mm).

[0083] Face number Surface type radius of curvature thickness Refractive index Abbe number surf1 aspherical 5.729 3.197 1.50 81.56 surf2 aspherical -1768.041 0.697 surf3(STO) spherical endless -0.088 surf4 aspherical 12.835 0.823 1.64 23.53 surf5 aspherical 7.278 1.618 surf6 aspherical -48.585 1.371 1.64 23.53 surf7 aspherical -25.779 0.796 surf8 aspherical 45.848 2.637 1.54 55.71 surf9 aspherical -7.480 0.200 surf10 aspherical .8.644 2.298 1.64 23.53 surf11 aspherical -18.584 1.014 surf12 aspherical -11.796 1.503 1.54 55.71 surf13 aspherical 7.859 0.702 surf14 spherical endless 0.300 1.52 64.20 surf15 spherical endless 0.200 surf16(IMA) spherical endless 0.000

[0084] Table 1

[0085] In this embodiment, the object-side surface and image-side surface of each lens of the fixed-focus lens, from the first lens L1 to the sixth lens L6, are aspherical. The surface shape x of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0086]

[0087] Where x is the distance vector from the vertex of the aspherical surface at a height h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 2 shows the conic coefficient (k) and higher-order coefficients A4, A6, A8, A4, and A5 that can be used for each aspherical mirror in this embodiment. 10 A 12 A 14 and A 16 .

[0088] Number / Coefficient k A4 A6 A8 A10 A12 A14 A16 surf1 0.27 -2.17E-04 -9.43E-06 -3.89E-08 -1.46E-08 -4.22E-10 0.00E+00 0.00E+00 surf2 0.00 3.46E-05 3.70E-05 -3.63E-06 2.04E-07 -3.74E-09 0.00E+00 0.00E+00 surf4 -3.29 -1.55E-03 1.59E-04 -9.86E-06 5.19E-07 -4.72E-09 0.00E+00 0.00E+00 surf5 -5.05 -2.51E-04 1.16E-04 -4.82E-06 8.34E-08 2.38E-08 0.00E+00 0.00E+00 surf6 90.00 -2.36E-03 -3.92E-06 -6.02E-06 4.18E-07 -2.18E-08 0.00E+00 0.00E+00 surf7 -2.99 -3.27E-03 5.61E-05 -2.71E-06 2.84E-07 -7.27E-09 0.00E+00 0.00E+00 surf8 89.43 -2.69E-03 1.79E-05 -5.26E-07 1.61E-07 -4.08E-09 0.00E+00 0.00E+00 surf9 -14.06 -2.10E-03 1.47E-06 -8.93E-07 -1.79E-08 2.26E-09 0.00E+00 0.00E+00 surf10 -21.10 -1.06E-03 -8.43E-06 -2.33E-06 5.89E-08 -2.72E-10 0.00E+00 0.00E+00 surf11 -90.00 6.78E-04 -4.75E-05 5.85E-07 5.64E-11 -2.40E-11 0.00E+00 0.00E+00 surf12 -0.50 -9.74E-04 3.67E-05 -2.52E-07 -1.76E-10 317E-12 0.00E+00 0.00E+00 surf13 -19.89 -7.09E-04 1.49E-05 -2.72E-07 1.86E-09 3.65E-12 0.00E+00 0.00E+00

[0089] Table 2

[0090] The fixed-focus lens in this embodiment has an aperture factor (FNO) of 2.2 and a field of view (FOV) of 63°.

[0091] Figure 2 The optical distortion curve of the fixed-focus lens of Example 1 is shown, with a maximum absolute value of optical distortion of 0.86%. According to... Figure 2 As can be seen, the fixed-focus lens given in Example 1 can achieve low distortion and has good aberration correction capability, thus achieving good image quality.

[0092] Example 2

[0093] The following is for reference Figures 3 to 4 This application describes a fixed-focus lens according to Embodiment 2. For the sake of brevity, descriptions similar to those in Embodiment 1 will be omitted in Embodiment 2 and the following embodiments.

[0094] like Figure 3As shown, in this embodiment, the fixed-focus lens includes, in sequence along the optical axis from the object side to the image side: aperture stop STO, first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5 and sixth lens L6.

[0095] In this embodiment, the first lens L1 has positive optical power, with its object-side surface (surf2) being convex and its image-side surface (surf3) being concave; the second lens L2 has positive optical power, with its object-side surface (surf4) being concave and its image-side surface (surf5) being convex; the third lens L3 has negative optical power, with its object-side surface (surf6) being concave and its image-side surface (surf7) being concave; the fourth lens L4 has positive optical power, with its object-side surface (surf8) being convex and its image-side surface (surf9) being convex; the fifth lens L5 has positive optical power, with its object-side surface (surf10) being convex and its image-side surface (surf11) being concave; and the sixth lens L6 has negative optical power, with its object-side surface (surf12) being concave and its image-side surface (surf13) being concave. The protective glass CG has an object-side surface (surf14) and an image-side surface (surf15). Light incident from the object side passes sequentially through the surfaces of each optical element and is finally imaged onto the imaging surface (IMA) (surf16).

[0096] In this embodiment, the first lens L1 is made of glass, while the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are all made of plastic.

[0097] Table 3 shows some basic parameters of each lens in the fixed-focus lens of this embodiment, including surface type, radius of curvature, thickness, refractive index of the material, and Abbe number. The units for radius of curvature and thickness / distance are millimeters (mm).

[0098] Face number Surface type radius of curvature thickness Refractive index Abbe number surf1(STO) spherical endless -0.923 surf2 spherical 5.825 1.940 1.50 81.61 surf3 spherical 1940.777 0.585 surf4 aspherical -37.927 1.160 1.54 55.71 surf5 aspherical -30.657 0.383 surf6 aspherical -25.473 0.606 1.61 26.90 surf7 aspherical 24.766 0.941 surf8 aspherical 27.407 3.000 1.54 55.71 surf9 aspherical -34.160 1.474 surf10 aspherical 18964 3.000 154 5571 surf11 aspherical 37.155 1.892 surf12 aspherical -8.366 1.308 1.54 55.71 surf13 aspherical 15.542 0413 surf14 spherical endless 0.300 1.52 64.20 surf15 spherical endless 0.200 surf16(IMA) spherical endless 0.000

[0099] Table 3

[0100] In this embodiment, the object-side surface and image-side surface of the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 are all aspherical, and the surface shape of each aspherical lens can be defined by formula (1) given in the above embodiment 1.

[0101] Table 4 shows the conic coefficient (k) and higher-order coefficients A4, A6, A8, and A6 that can be used for each aspherical mirror in this embodiment. 10 A 12 A 14 and A 16 .

[0102] Number / Coefficient k A4 A6 A8 A10 A12 A14 A16 surf4 90.00 -8.97E-04 1.43E-05 1.02E-06 -9.02E-08 2.12E-09 0.00E+00 0.00E+00 surf5 -34.98 -1.97E-03 2.81E-05 3.59E-07 -7.68E-08 -2.77E-09 0.00E+00 0.00E+00 surf6 38.71 1.75E-03 -5.39E-05 6.02E-07 2.38E-07 -1.25E-08 0.00E+00 0.00E+00 surf7 -99.47 2.67E-03 -7.04E-05 2.79E-06 6.06E-08 4.91E-09 0.00E+00 0.00E+00 surf8 -117.28 -1.40E-03 -4.83E-05 2.12E-06 -3.97E-07 1.43E-08 0.00E+00 0.00E+00 surf9 47.23 -1.89E-03 -7.65E-06 8.38E-07 -6.05E-08 1.65E-09 0.00E+00 0.00E+00 surf10 -25.17 -1.00E-03 -4.05E-05 -2.18E-07 3.19E-08 -3.87E-10 0.00E+00 0.00E+00 surf11 0.00 3.90E-04 -4.57E-05 9.78E-07 -9.45E-09 1.12E-11 0.00E+00 0.00E+00 surf12 -0.45 -5.07E-04 4.16E-05 -5.37E-07 2.55E-09 -9.14E-12 0.00E+00 0.00E+00 surf13 -65.21 -6.41E-04 2.42E-05 -8.39E-07 1.34E-08 -7.12E-11 0.00E+00 0.00E+00

[0103] Table 4

[0104] The fixed-focus lens in this embodiment has an aperture factor (FNO) of 2.2 and a field of view (FOV) of 64°.

[0105] Figure 4 The optical distortion curve of the fixed-focus lens in Example 2 is shown, with a maximum absolute value of 1.85% for optical distortion. According to... Figure 4 As can be seen, the fixed-focus lens given in Example 2 can achieve low distortion and has good aberration correction capability, thus achieving good image quality.

[0106] Example 3

[0107] The following is for reference Figures 5 to 6 Describes a fixed-focus lens according to Embodiment 3 of this application.

[0108] like Figure 5 As shown, in this embodiment, the fixed-focus lens includes, in sequence along the optical axis from the object side to the image side: a first lens L1, an aperture stop STO, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6.

[0109] In this embodiment, the first lens L1 has positive optical power, with its object-side surface surf1 being convex and its image-side surface surf2 being convex; the second lens L2 has negative optical power, with its object-side surface surf4 being convex and its image-side surface surf5 being concave; the third lens L3 has positive optical power, with its object-side surface surf6 being convex and its image-side surface surf7 being convex; the fourth lens L4 has negative optical power, with its object-side surface surf8 being convex and its image-side surface surf9 being concave; the fifth lens L5 has positive optical power, with its object-side surface surf10 being convex and its image-side surface surf11 being convex; and the sixth lens L6 has negative optical power, with its object-side surface surf12 being concave and its image-side surface surf13 being concave. The protective glass CG has an object-side surface surf14 and an image-side surface surf15. Light incident from the object side passes sequentially through the surfaces of each optical element and is finally imaged onto the imaging surface (IMA) surf16.

[0110] In this embodiment, the first lens L1 is made of glass, while the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are all made of plastic.

[0111] Table 5 shows some basic parameters of each lens in the fixed-focus lens of this embodiment, including surface type, radius of curvature, thickness, refractive index of the material, and Abbe number. The units for radius of curvature and thickness / distance are millimeters (mm).

[0112] Face number Surface type radius of curvature thickness Refractive index Abbe number surf1 spherical 7.106 3.000 1.49 70.44 surf2 spherical -235.756 0.194 surf3(STO) spherical endless 0.100 surf4 aspherical 15.004 0.960 1.66 20.38 surf5 aspherical 8.863 1.286 surf6 aspherical 75.975 2.315 1.54 55.71 surf7 aspherical -17.708 1.008 surf8 aspherical 51.201 1.143 1.61 25.58 surf9 aspherical 19.454 0.233 surf10 aspherical 14.905 3.500 1.54 55.71 surf11 aspherical -263.357 2.000 surf12 aspherical -8.403 1.486 1.54 55.71 surf13 aspherical 12.123 0.502 surf14 spherical endless 0.300 1.52 64.20 surf15 spherical endless 0.200 suff16(IMA) spherical endless 0.000

[0113] Table 5

[0114] In this embodiment, the object-side surface and image-side surface of the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 are all aspherical, and the surface shape of each aspherical lens can be defined by formula (1) given in the above embodiment 1.

[0115] Table 6 shows the conic coefficient (k) and higher-order coefficients A4, A6, A8, and A6 that can be used for each aspherical mirror in this embodiment. 10 A 12 A 14 and A 16 .

[0116] Number / Coefficient k A4 A6 A8 A10 A12 A14 A16 surf4 6.24 -1.89E-03 2.28E-06 6.94E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf5 3.14 -2.41E-03 -1.99E-05 2.11E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf6 -60.50 -8.39E-04 -3.66E-05 -2.81E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf7 14.55 -1.99E-03 5.80E-06 -8.55E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf8 -46.42 -2.75E-03 -8.26E-06 7.20E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf9 13.13 -2.43E-03 -8.88E-06 9.38E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf10 -4.28 -1.09E-03 -2.51E-05 4.31E-08 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf11 -16.56 4.83E-04 -3.29E-05 2.67E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf12 -0.71 -1.09E-03 3.17E-05 -1.13E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf13 -66.79 -1.44E-04 -7.65E-06 1.00E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00

[0117] Table 6

[0118] The fixed-focus lens in this embodiment has an aperture factor (FNO) of 2.2 and a field of view (FOV) of 63°.

[0119] Figure 6 The optical distortion curve of the fixed-focus lens in Example 3 is shown, with a maximum absolute value of 1.34% for optical distortion. According to... Figure 6 As can be seen, the fixed-focus lens given in Example 3 can achieve low distortion and has good aberration correction capability, thus achieving good image quality.

[0120] Example 4

[0121] The following is for reference Figures 7 to 8 Describes a fixed-focus lens according to Embodiment 4 of this application.

[0122] like Figure 7 As shown, in this embodiment, the fixed-focus lens includes, in sequence along the optical axis from the object side to the image side: a first lens L1, a second lens L2, an aperture stop STO, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6.

[0123] In this embodiment, the first lens L1 has positive optical power, with its object-side surface surf1 being convex and its image-side surface surf2 being concave; the second lens L2 has negative optical power, with its object-side surface surf3 being convex and its image-side surface surf4 being concave; the third lens L3 has positive optical power, with its object-side surface surf6 being convex and its image-side surface surf7 being convex; the fourth lens L4 has positive optical power, with its object-side surface surf8 being convex and its image-side surface surf9 being concave; the fifth lens L5 has positive optical power, with its object-side surface surf10 being convex and its image-side surface surf11 being concave; and the sixth lens L6 has negative optical power, with its object-side surface surf12 being concave and its image-side surface surf13 being concave. The protective glass CG has an object-side surface surf14 and an image-side surface surf15. Light incident from the object side passes sequentially through the surfaces of each optical element and is finally imaged onto the imaging surface (IMA) surf16.

[0124] In this embodiment, the first lens L1 is made of glass, while the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are all made of plastic.

[0125] Table 7 shows some basic parameters of each lens in the fixed-focus lens of this embodiment, including surface type, radius of curvature, thickness, refractive index of the material, and Abbe number. The units for radius of curvature and thickness / distance are millimeters (mm).

[0126] Face number Surface type radius of curvature thickness Refractive index Abbe number surf1 spherical 8.150 2.514 1.57 62.96 surf2 spherical 99.266 0.314 surf3 aspherical 10.331 0.692 1.64 23.53 surf4 aspherical 6.283 0.717 surf5 (STO) aspherical endless 0.100 surf6 aspherical 108.744 2.942 1.54 55.71 surf7 spherical -39.763 1.152 surf8 spherical 8.380 1.421 1.54 55.71 surf9 spherical 13.998 1.210 surf10 aspherical 12.175 2.286 1.54 55.71 surf11 aspherical 34.286 2.000 surf12 aspherical -10.391 2.738 1.64 23.53 surf13 aspherical 16.682 0.501 surf14 spherical endless 0.300 1.52 64.20 surf15 spherical endless 0.200 surf16(IMA) spherical endless 0.000

[0127] Table 7

[0128] In this embodiment, the object-side surface and image-side surface of the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 are all aspherical, and the surface shape of each aspherical lens can be defined by formula (1) given in the above embodiment 1.

[0129] Table 8 shows the conic coefficient (k) and higher-order coefficients A4, A6, A8, and A6 that can be used for each aspherical mirror in this embodiment. 10 A 12 A 14 and A 16 .

[0130] Number / Coefficient k A4 A6 A8 A10 A12 A14 A16 Surf3 3.48 -2.12E-03 3.04E-05 -7.66E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 Surf4 1.39 -2.41E-03 2.81E-05 -2.18E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf6 90.00 -5.50E-04 -7.88E-06 -1.28E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf7 91.18 -2.08E-03 2.11E-05 -1.21E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf8 1.00 -1.51E-03 7.14E-07 -1.16E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf9 5.44 -8.99E-04 -1.66E-05 -7.22E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf10 -1.80 -1.05E-03 -2.64E-05 -1.90E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf11 -1.00 1.61E-04 -5.13E-05 7.61E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf12 -0.67 -9.19E-04 8.65E-06 2.35E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 surf13 -48.46 -2.17E-04 -4.12E-06 5.15E-08 0.00E+00 0.00E+00 0.00E+00 0.00E+00

[0131] Table 8

[0132] The fixed-focus lens in this embodiment has an aperture factor (FNO) of 2.2 and a field of view (FOV) of 63°.

[0133] Figure 8The optical distortion curve of the fixed-focus lens in Example 4 is shown, with a maximum absolute value of 1.48% for optical distortion. According to... Figure 8 As can be seen, the fixed-focus lens given in Example 4 can achieve low distortion and has good aberration correction capability, thus achieving good image quality.

[0134] In summary, the fixed-focus lenses in Embodiments 1 to 4 satisfy the conditions shown in Table 9 below.

[0135] Conditional / Example 1 2 3 4 3.48 ≤ Vd1 / F1 ≤ 7.73 7.12 6.96 4.97 4.09 1.8 ≤ F1 / R11 ≤ 2.16 2.00 2.01 1.99 1.89 1.5 ≤ |F23 / F| ≤ 7.5 3.11 1.57 7.16 3.90 12 ≤ |F23 / (d2+d3) | ≤ 32 19.83 12.33 30.75 15.13 0.22≤|(R21+R22) / (R31+R32)|≤2.9 0.27 97.01 0.41 0.24 0.2 ≤ |F4 / (R41+R42) 1 ≤ 4.3 0.32 4.26 0.73 1.59 -1.5 ≤ F56 / F ≤ -0.23 -0.42 -0.93 -1.32 -1.17 1≤|(R12+R52) / (R12-R52)|≤7.5 1.02 1.04 18.08 2.06 1.98 ≤ TTL / H ≤ 2.4 2.03 2.02 2.14 2.24 1.21 ≤ TTL / F ≤ 1.47 1.24 1.24 1.30 1.35 3.62 ≤ CTmax / CTmin ≤ 5.2 3.86 4.95 3.64 4.25 0.7 ≤ d4 / Nd4 ≤ 2.1 1.72 1.95 0.71 0.93 -3.2≤(R51+R52) / (R51-R52)≤-0.75 -2.74 -3.08 -0.89 -2.10 1.6mm≤|(R61+R62)*F6 / (R61-R62)|≤3.49mm 1.71 2.98 1.63 2.21 1.58 ≤ F / H ≤ 1.66 1.64 1.64 1.66 1.66

[0136] Table 9

[0137] According to the fixed-focus lens provided in this application, by reasonably setting the surface shape and optical power distribution of each lens, the incident light path of the optical system can be effectively controlled, the light beam can be raised to meet the target surface size requirements, and the target surface can reach 17mm. It can converge the incident light beam with a large field of view into the optical system as much as possible, expand the field of view of the optical system, and make the field of view FOV ≥ 63°. At the same time, it can better balance various aberrations of the optical system and effectively correct the optical distortion of the optical system, making the absolute value of optical distortion less than or equal to 1.85%, reducing the degree of image distortion. At the same time, it can achieve miniaturization, with the total length of the optical system TTL < 21mm.

[0138] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A fixed focus lens characterized by, In order from the object side to the image side along the optical axis, the fixed focus lens comprises: a first lens with positive refractive power, the object side surface of which is convex; a second lens with refractive power, the object side surface of which is concave when the refractive power of the second lens is positive, and the image side surface of which is convex; the object side surface of which is convex when the refractive power of the second lens is negative, and the image side surface of which is concave; a third lens with refractive power, the image side surface of which is convex when the refractive power of the third lens is positive; the image side surface of which is concave when the refractive power of the third lens is negative; a fourth lens, the object side surface of which is convex; a fifth lens with refractive power, the object side surface of which is convex when the refractive power of the fifth lens is positive; the object side surface of which is concave when the refractive power of the fifth lens is negative; and a sixth lens with negative refractive power, both the object side surface and the image side surface of which are concave, wherein the number of lenses with refractive power in the fixed focus lens is six; the refractive power of the second lens is negative, the refractive power of the third lens is positive, the refractive power of the fourth lens is positive, and the refractive power of the fifth lens is positive or negative; or the refractive power of the second lens is negative, the refractive power of the third lens is positive, the refractive power of the fourth lens is negative, and the refractive power of the fifth lens is positive; or the refractive power of the second lens is positive, the refractive power of the third lens is negative, the refractive power of the fourth lens is positive, and the refractive power of the fifth lens is positive; both the image side surface of the first lens and the image side surface of the fifth lens are convex or concave; The effective focal length F6 of the sixth lens, the radius of curvature R61 of the object side surface of the sixth lens, and the radius of curvature R62 of the image side surface of the sixth lens satisfy: 1.6mm≤|(R61+R62) F6 / (R61-R62)|≤3.49mm; the combined effective focal length F56 of the fifth lens and the sixth lens and the total effective focal length F of the fixed focus lens satisfy: -1.5≤F56 / F≤-0.

23.

2. The fixed focal length lens of claim 1, wherein, the Abbe number Vd1 of the first lens and the effective focal length F1 of the first lens satisfy: 3.48≤Vd1 / F1≤7.

73.

3. The prime lens according to claim 1, wherein the effective focal length F1 of the first lens and the radius of curvature R11 of the object side surface of the first lens satisfy: 1.80≤F1 / R11≤2.

16.

4. The prime lens of claim 1, wherein, the combined effective focal length F23 of the second lens and the third lens and the total effective focal length F of the fixed focus lens satisfy: 1.5≤|F23 / F|≤7.

5.

5. The prime lens of claim 1, wherein, the combined effective focal length F23 of the second lens and the third lens, the central thickness value d2 of the second lens, and the central thickness value d3 of the third lens satisfy: 12≤|F23 / (d2+d3)|≤32.

6. The prime lens of claim 1, wherein, the effective focal length F4 of the fourth lens, the radius of curvature R41 of the object side surface of the fourth lens, and the radius of curvature R42 of the image side surface of the fourth lens satisfy: 0.2≤|F4 / (R41+R42)|≤4.

3.

7. The prime lens of claim 1, wherein, the radius of curvature R12 of the image side surface of the first lens and the radius of curvature R52 of the image side surface of the fifth lens satisfy: 1≤|(R12+R52) / (R12-R52)|≤2.

06.

8. The prime lens according to claim 1, wherein the total length TTL of the optical system of the fixed focus lens and half of the diagonal length H of the effective pixel area on the imaging plane of the fixed focus lens satisfy: 1.98≤TTL / H≤2.

4.

9. The prime lens according to claim 1, wherein An optical total track length TTL of the fixed focus lens and a total effective focal length F of the fixed focus lens satisfy: 1.21≤TTL / F≤1.

47.

10. The prime lens according to any one of claims 1-9, wherein, A maximum value CTmax of a center thickness of each lens on the optical axis in the fixed focus lens and a minimum value CTmin of the center thickness of each lens on the optical axis in the fixed focus lens satisfy: 3.62≤CTmax / CTmin≤5.

2.

11. The prime lens according to any one of claims 1-9, wherein, A center thickness value d4 of the fourth lens and a refractive index Nd4 of the fourth lens satisfy: 0.7≤d4 / Nd4≤2.

1.

12. The prime lens according to any one of claims 1-9, wherein, A radius of curvature R51 of an object side surface of the fifth lens and a radius of curvature R52 of an image side surface of the fifth lens satisfy: -3.2≤(R51+R52) / (R51-R52)≤-0.

75.

13. The prime lens according to any one of claims 1-9, wherein, A radius of curvature R21 of an object side surface of the second lens, a radius of curvature R22 of an image side surface of the second lens, a radius of curvature R31 of an object side surface of the third lens, and a radius of curvature R32 of an image side surface of the third lens satisfy: 0.22≤|(R21+R22) / (R31+R32)|≤0.

41.

14. The prime lens according to any one of claims 1-9, wherein, A total effective focal length F of the fixed focus lens and a half H of a diagonal length of an effective pixel area on an imaging plane of the fixed focus lens satisfy: 1.58≤F / H≤1.

66.

15. The prime lens according to any one of claims 1-9, wherein, The fixed focus lens satisfies at least one of the following conditions: 0.24≤|(R21+R22) / (R31+R32)|≤0.41; |(R21+R22) / (R31+R32)|=97.01; 4.09≤Vd1 / F1≤7.12; 1.89≤F1 / R11≤2.01; 1.57≤|F23 / F|≤7.16; 12.33≤|F23 / (d2+d3)|≤30.75; 0.2≤|F4 / (R41+R42)|≤4.3; -1.32≤F56 / F≤-0.42; 1.02≤|(R12+R52) / (R12-R52)|≤2.06; |(R12+R52) / (R12-R52)|=18.08; 2.02≤TTL / H≤2.24; 1.24≤TTL / F≤1.35; 3.64≤CTmax / CTmin≤4.95; 0.71≤d4 / Nd4≤1.95; -3.08≤(R51+R52) / (R51-R52)≤-0.89; 1.63 mm ≤ |(R61+ R62) F6 / (R61- R62) | ≤ 2.98 mm; 1.64≤F / H≤1.66; Wherein, R21 is the curvature radius of the object side of the second lens, R22 is the curvature radius of the image side of the second lens, Vd1 is the Abbe number of the first lens, F1 is the effective focal length of the first lens, R11 is the curvature radius of the object side of the first lens, F23 is the combined effective focal length of the second lens and the third lens, F is the total effective focal length of the fixed focus lens, d2 is the central thickness value of the second lens, d3 is the central thickness value of the third lens, F4 is the effective focal length of the fourth lens, R41 is the curvature radius of the object side of the fourth lens, R42 is the curvature radius of the image side of the fourth lens, F56 is the combined effective focal length of the fifth lens and the sixth lens, R12 is the curvature radius of the image side of the first lens, R52 is the curvature radius of the image side of the fifth lens, TTL is the total track length of the optical system of the fixed focus lens, H is half of the diagonal length of the effective pixel area on the imaging plane of the fixed focus lens, CTmax is the maximum value of the central thickness of each lens on the optical axis in the fixed focus lens, CTmin is the minimum value of the central thickness of each lens on the optical axis in the fixed focus lens, d4 is the central thickness value of the fourth lens, Nd4 is the refractive index of the fourth lens, R51 is the curvature radius of the object side of the fifth lens, R61 is the curvature radius of the object side of the sixth lens, and R62 is the curvature radius of the image side of the sixth lens.

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